Physical forms of beta-L-2'-deoxythymidine are disclosed that can be characterized- by physical appearance, purity levels, Infra-Red and Raman spectroscopy, X-ray powder diffraction patterns, thermal properties, and methods of manufacture. These forms of beta-L-2'-deoxythymidine can be used in the manufacture of other forms of beta-L-2'-deoxythymidine, or in pharmaceutical compositions. Particularly preferred uses are in the treatment of hepatitis B.